Body Mass Index Trajectories From Birth to Midlife and Vertebral Dimensions in Midlife: the Northern Finland Birth Cohort 1966 Study

Abstract

Vertebral fracture risk is higher among individuals with small vertebral dimensions. Obesity is a global health problem and may also contribute to bone size and fracture risk. In this work we report the association between life course body mass index (BMI) and vertebral cross-sectional area (CSA) in midlife. The Northern Finland Birth Cohort 1966 study with its 46-year follow-up provided the material for this study. A subsample of 780 individuals had attended lumbar magnetic resonance imaging (MRI) at the age of 46 years, and had records of objectively measured BMI from the ages of 0, 7, 15, 31, and 46 years. Of these, MRI-derived data on vertebral size was available for 682 individuals. We identified latent lifelong BMI trajectories by performing latent class growth modeling (LCGM) on the BMI data, and then used sex-stratified linear regression models to compare the identified trajectory groups in terms of midlife vertebral CSA. Gestational age, education years, adult height, lifelong physical activity, lifelong smoking history, and adulthood diet were assessed as potential confounders. Three distinct trajectory groups ("stable slim," "stable average," and "early onset overweight") were identified among both sexes. Comparisons to the stable slim trajectory revealed that vertebral CSA was significantly (p < 0.001) larger among the stable average and early onset overweight trajectories (69.8 and 118.6 mm 2 larger among men, 57.7 and 106.1 mm 2 larger among women, respectively). We conclude that lifelong BMI has a positive association with midlife vertebral size among both sexes. Future studies should characterize the mediating factors of this association.

Group‐based trajectory modeling of body mass index and body size over the life course: A scoping review

“…The mean trajectory duration (time between first and last anthropometric measurement) was 29.2 years (SD = 17.1). 22 studies that began growth assessment in childhood 5,14,18,20,22,30–32,36,38,41–51 and extended into adulthood. Of these 22 studies with growth trajectories beginning in childhood, five studies 20,22,38,41,51 had measures until young adulthood (19–23 years old), 12 studies 16,30–32,36,42–50 had measures until midadulthood (38–50 years old), and five studies 5,14,17,18,46 had measures until older adulthood (60–80 years old).…”

“…22 studies that began growth assessment in childhood 5,14,18,20,22,30–32,36,38,41–51 and extended into adulthood. Of these 22 studies with growth trajectories beginning in childhood, five studies 20,22,38,41,51 had measures until young adulthood (19–23 years old), 12 studies 16,30–32,36,42–50 had measures until midadulthood (38–50 years old), and five studies 5,14,17,18,46 had measures until older adulthood (60–80 years old). The remaining studies ( n = 37) 15,19,21–29,33–35,37,39,40,52–72 did not include any childhood measures, and only included measures >18 years of age.…”

Lifelong smoking trajectories of Northern Finns are characterized by sociodemographic and lifestyle differences in a 46-year follow-up

“…Participants underwent objective height and weight measurements according to previously described methods as part of routine growth monitoring in childhood and adolescence, and as part of the clinical examinations at the ages of 31 and 46 38 . At each follow-up point, body mass index (BMI, kg/m 2 ) was calculated as weight (kg) divided by height (m) squared.…”

Eating Behavior Traits, Weight Loss Attempts, and Vertebral Dimensions Among the General Northern Finnish Population

“…Vertebral fragility fractures are a typical manifestation of osteoporosis 5,6 , and small vertebral dimensions are a well-established risk factor for vertebral fracturing 3,7 . Interestingly, vertebrae enlarge in size well beyond adolescence 8,9 , and previous studies have associated lifestyle choices in adulthood with midlife vertebral size [10][11][12] . Therefore, further data on the association between lifestylerelated factors and vertebral size across the lifespan may provide valuable tools for fracture risk estimation and fracture prevention.…”